It is common to employ a liquid electrolyte in an electrochemical element such as a primary battery, a secondary battery or a capacitor. However, the liquid electrolyte has drawbacks in that liquid leakage occurs and it cannot ensure long-term reliability.
The use of a solid electrolyte for overcoming the above drawbacks of the liquid electrolyte is known. The application of the solid electrolyte to the above electrochemical element enables not only providing an element which is free from liquid leakage and ensures high reliability but also realizing miniaturization and weight reduction of the element per se.
A variety of polymeric solid electrolytes have been studied for recent years. The polymeric solid electrolytes not only are so flexible that appropriate application can be made irrespective of a volume change which occurs during the ion/electron exchange reaction between the electrode and each polymeric solid electrolyte but also has the above-mentioned general advantages of the solid electrolytes.
The use of a complex composed of a polyethylene oxide having polyether structure and an alkali metal salt such as a lithium salt is known among such a variety of polymeric solid electrolytes.
Japanese Patent Laid-open Publication No. 25353/1993 describes a polymeric solid electrolyte composed mainly of a crosslinked resin comprising a copolymer of a polyoxyalkylene diester compound, a polymethoxyoxyalkylene ester compound and an oxy compound having double bond, and an inorganic salt. Further, Japanese Patent Laid-open Publication No. 223842/1994 describes a polymeric solid electrolyte composed of an organic polymer having a carbonate group as a functional group and a metal salt.
However, these solid electrolytes generally have lower ionic conductivity than those of the liquid electrolytes, so that it is difficult to obtain a primary or secondary battery having excellent discharge characteristics therefrom.
Under the circumstance, there are demands on the development of a polymeric solid electrolyte which can satisfy the requirements such as high ionic conductivity and high electrochemical stability, and the development of a novel polymer which can be a polymer matrix of the above polymeric solid electrolyte. Further, there are demands on the development of a novel compound which can be a starting monomer capable of forming the above polymer.